DE3033207A1 - OPTICAL SCAN SYSTEM WITH A WASTE CORRECTION FUNCTION - Google Patents

Description

The invention relates to an optical scanning system in which the pitch joints of the scanning lines are eliminated are.

So far, the most diverse light beam scanning systems, 25 which has a deflecting reflection surface, for example one Using rotatable polygon mirrors has been proposed in which, even if the direction of reciprocation of the light beam that is deflected and scanned varies in a plane perpendicular to the deflection surface 30 is due to the drop in the deflection reflection surface

surface, no joint occurs when the scanning lines are divided on the scanned surface (the scanning material). Here, the deflecting surface refers to the light beam surface that passes through over time 35 from the Abienk reflection surface of the deflection element

V / 19

130012/0852

Deutsche Bank (Munich) Account 51/61070

Dresdner Bank (Munich) Account 3939844

Postal check (Munich) account 670-43-804

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deflected light beam is formed.

For example, the optical system of US Pat. No. 3,750,189 has between the deflector and the sensing material a beam focusing device and a second collecting device, and that of the deflecting mirror The reflected light beam is collimated by the beam focusing device. If the optical

IQ System is equipped with such a collimation function is the shape of the beam focusing device limited, so that the degree of freedom, the image quality on the scanned surface and the Elongation characteristic affecting the scanning speed

■ ic makes constant, improved, humiliated and necessarily a good quality cannot be achieved if not the number of lenses that the second one Form collecting device is increased.

on In US-PS 3,865,465 a certain predetermined

Restriction of the ratio of the focal lengths two degrees below ■ different lenses are imposed which form the optical system between the deflecting element and the scanning material. The fulfillment of this restriction is equivalent

with the collimation of the light beam in a cross section perpendicular to the deflecting surface between the two different lenses. Consequently, in this example too, the degree of freedom through which the image quality and the strain characteristics are corrected well as above explained, reduced; this is not preferable.

According to US Pat. No. 3,946,150, a cylindrical lens is between a lens that has elongation characteristics to achieve a uniform scanning speed,

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and the scanning material. With such a structure, a good image cannot be obtained if not the position of the cylinder lens is brought close to the scanning material. When the cylinder lens is close to the scanning material comes, the cylinder lens becomes longer in the direction of the baseline as the scan width becomes longer; this means that a compact structure can no longer be achieved.

In US-PS 4,123,135 an optical system for

Correction of the slope of the deflecting reflection surface of the deflector described. This system is characterized by the fact that a cylindrical lens is an axis perpendicular to the deflecting surface and negative refractive power in the deflecting surface, but no refractive power in one Has a cross-section perpendicular to the deflecting surface, in the optical imaging system between the deflecting element and the scanning material is arranged. This imaging optical system has three lenses.

It is the object of the invention to eliminate the above-mentioned disadvantages of the conventional scanning devices and to provide an optical scanning system in which the waste of the deflector is reduced in a simple and compact manner Construction can be corrected.

Furthermore, an optical scanning system is to be provided in which IThe beam scanning speed on the off nr \ keyed surface is constant. In addition, a

Optical scanning system can be created in which the position of the scanning line on the scanned surface can be easily adjusted.

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In the optical scanning system according to the invention, has

a scanning optical imaging system interposed between the Deflection element and the scanning material is arranged - one after the other from the deflection element side spherical single lens and a single lens with a toric surface to thereby accomplish the task to solve. This means that the scanning optical system according to the invention with a light source device, a first optical imaging system for linear imaging of the light beam from the light source direction a deflecting element whose deflecting reflection surface is close to the linear image, and a second imaging optical system for imaging the linear image as Is provided on the scanning material. The second optical imaging system has - successively from the deflector side - a spherical single lens and a toric single lens. With "toric Lens "here is meant a lens which has a refractive power in orthogonal directions in an orthogonal plane to the optical axis of the lens, the refractive power being different in the orthogonal directions is.

The toric according to the invention described above The surface has a radius of curvature in the deflecting surface that is greater than its radius of curvature in the Plane perpendicular to the deflecting surface.

" _N In the optical scanning system according to the invention, the toric lens is a positive meniscus lens which has a surface with a negative refractive power on the deflecting element side and a surface with a positive refractive power on the scanning material side in a transverse direction.

oc section, which is the optical axis of the spherical

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Contains single lens and is perpendicular to the deflecting surface that is deflected by the deflecting element Beam is formed.

In the case of the optical scanning system according to the invention, this has

scanning optical imaging system interposed between the deflector and the scanning material is arranged, no beam focusing device that once

IQ steering element deflected light beam collimated. this means that the system according to the invention does not use a device with a collimation function; therefore the degree of freedom with which the image quality and the expansion or deformation characteristics

■ rc of the optical imaging system can be corrected well, no restrictions imposed. This leads to the realization of a simple and compact construction.

Furthermore, according to the invention, a toric lens on the

ng side of the spherical single lens provided that the Sensing material is adjacent. This can be the elongation characteristic compared with the case of a cylinder lens correct and make the device compact. This means that if a cylinder lens is used, its refractive power in the deflection surface is zero and there is no degree of freedom with which the curvature of field is corrected. In contrast, a toric lens has a power in the deflecting surface and can therefore correct the curvature of field. Hence, even if efforts are made, the To make the scanning optical imaging system compact by using a cylindrical lens, a large curvature of field on. For the reasons explained above, it is impossible to do this through the cylinder lens itself correct. In contrast, it has a toric lens

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a degree of freedom for correction; this can the scanning optical imaging system can be kept compact.

"Further, in the invention, the first imaging optical system in a direction perpendicular to its optical axis and perpendicular to the longitudinal direction of the Linear image moves; This brings about a position adjustment of the scanning line on the scanning surface. at According to the present invention, the first imaging optical system can have a power in only one direction to have. Consequently, when the first imaging optical system moves to adjust the scan line position the placement accuracy of the first imaging optical system after it has been moved is shown in with respect to the direction in which the first imaging optical system has no refractive power.

The invention is described in more detail below using exemplary embodiments with reference to the drawing. Show it:

1 shows the principle of the optical scanning system according to the invention ,

2 shows a cross section to explain the function in a plane parallel to the deflecting surface,

3 is a view for explaining the function in a cross section perpendicular to the deflecting surface,

Fig. 4 an explanation of the angle £. with which the Principal ray, which is in the plane parallel to the deflecting surface is deflected, is incident on a lens with a toric surface,

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Pig.5, 6 and 7 the relationship between the image height and the angle ^ in the scanning lens system used in the present Invention is used,

8A and B show the shape of an embodiment of the scanning lens used in the invention;

FIGS. 9A and B show the various artifacts in FIG

Gaussian image plane of that shown in Figures 8A and B.

Lenses,

Figs. 10A and B show the shape of another embodiment the scanning lens used in the invention,

11A and B show the various artifacts in the

Gaussian image plane of the lenses shown in FIGS. 10A and B,

2ß Fig. 12 the setting of the position of the scanning line in the optical scanning system according to the invention,

13 and 14 show a mechanism for adjusting the position of the Scanning line in the optical Aboc according to the invention touch system, and

Fig. 15 is a schematic view of an embodiment of a laser beam printer in which the invention is applied.

Fig. 1 shows the structure according to the principle of the invention, ±> ei which a light source or a light source device 1, which has a light source and a condenser device, a linear imaging system 2, which the light emanating from -the light source device 1-

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beam into a linear image, a deflection element with a deflection reflection surface 3a near the point _r at which the light beam is _{made linearly convergent by the linear imaging system ς} , a spherical single lens 4 between the deflection element 3 and a material 6 to be scanned, and a Single lens 5 with a toric surface with a major axis and a minor axis which, with respect to the refractive power, are divided into two perpendicular

IQ th directions are different, are arranged in such a way that an image spot is formed on the scanning material 6 by the overall system of these lenses,
and that when the deflection element 3 is rotated, the imaging spot scans the scanning material 6. The main axis of the c toric surface lies in a plane parallel to

the deflector. The minor axis of the toric surface lies in a plane perpendicular to the deflecting surface and contains the center of curvature of the Main axis. The absolute value of the radius of curvature in

2Q pull on the main axis is greater than the absolute value
the radius of curvature with respect to the minor axis.

Fig. 2 is a view for explaining the function
in a cross section parallel to the deflecting surface

in the structure described above, in other words the plane which is the major axis of the toric
Lens 5 and the optical axis of the spherical single lens 4 contains. The light beam emitted by the light source device 1 passes through the cylindrical

Lens 2. It is then reflected by the reflective surface 3a of the deflector 3; at
Rotation of the deflecting element 3 deflects the reflected light beam. Furthermore, the deflected light beam on the scanning material 6 is caused by the spherical single lens 4 and the lens 5 with the toric upper

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surface composite system shown. The scanning speed of the image spot is kept constant.

_ς Fig. 3 is a developed view of the cross section perpendicular along the light beam in a direction perpendicular to the above-mentioned deflection, of the cross section that is for correcting the influence of the drop of the deflection member. The from the light source device 1

,,, sent light beam is through the linear imaging system 2 near the reflective surface 3a of the deflecting element 3 is shown linearly. The power of the Single lens 5 makes in this cross-section, unequal to the refractive power of the lens in the deflection surface, the

, r positional relationship between the reflective surface 3a of the deflection element 3 and the scanning material 6 due to the individual lens 5 and the spherical lens Single lens 4 composite system optical conjugated. Therefore changes even if the reflective

2Q surface 3a in a position 3'a in one direction is tilted perpendicular to the deflecting surface during the rotation of the deflecting element 3, which is passed through the lens system 4, 5 passing light beam as indicated by the dashed line, but none occurs Change of the image position on the scanning material 6.

The following is an explanation of how and why a good image quality and a uniform scanning speed on the scanning material in the case of the invention

30 according to the optical scanning system can be obtained, although the system has a simple and compact structure. When the aperture ratio is small, for example 1:30 - 1: 100, two single lenses are sufficient as a lens construction out to have a good sampling characteristic

35 to achieve.

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In general, in a lens system having a small aperture ratio, the aberration coefficients to be corrected are the astigmatism coefficient (II) and the distortion coefficient (V). For these aberration coefficients of the entire lens system, the following relationships exist between the characteristic coefficients a ^^, b ^ .., C ₁₁₁₁ , a ^, b ^ c _yi and the eigen coefficients Aoi, IBoi:

N
III = Σ (a _TTX . Aoi + b _TTT . Boi +

(D

V = Σ (a.Aoi + J ^ ₁ Boi +
i = l

The characteristic coefficients are constants determined by the paraxial relations and the material, and the eigen coefficients Aoi and Boi are coefficients which have the shape of the i. Determine the construction group. Equation (1) shows the general relationship when the number of art reduction groups is N. ( Lens Designing Method , by Matsui, Kyoritsu Publishing Co., Ltd.) -

Further, when each design group is a single lens, there is the following secondary relationship between the Eigencoefficients Aoi and © oi of each individual lens:

Aoi = oti IB ² Oi + ßi Boi + γι (2)

Here, <oii, Al and Vi are constants which are determined by the refractive index of the material of the individual lens.
-

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If equation 12) in equation · {1}. is used,

you get

N (3)

= Σ (ξ. TB ² _{+ η} TR "+ r )

oi

here J _{III ±} , £ _{χΙΙ ±} , J ₁₁₁₁ , J _{v ±} , £ _{yl and} j _{v ± are} constants which are determined by the characteristic coefficients and the constants Ki, β i and v ^ i.

In equation (3), when the desired values of the respective aberration coefficients by which the elongation characteristic is obtained with which a good image quality and a uniform scanning speed are obtained are selected and the number of lenses in the structure is 2 (N = 2) " , it is possible to simultaneously solve the equations IB ₁ and IB "have as unknowns" and obtain IB "and B ".

oil oz

IB. is determined as follows by the radius of curvature R. of the front surface of the i. Lens and the refractive index N. of the material of this lens (L ens

¹

Designing Method , by Matsui):

N. N. +1

^B oi ⁼ -

N '. + 1 N.

¹³ Oi

Oi ⁺ NT ^ (4).

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Thus, from the eigen coefficients E ₁ and IB "of the two groups obtained with the above results, the radii of curvature R ₁ and R" of the c front surfaces of the respective lenses can be obtained using equation (4). The radii of curvature R., and R ^ _{1 of} the back surfaces of the respective lenses can be obtained from the following equation:

N.-l

R ₁ , = (1-N ₁ ) Z (I - -I-) (5)

In the above description, each lens of the structure has been treated as a thin lens, its focal length ir is normalized to 1.

In the actual system of FIG. 2, it should be assumed that the refractive powers of lenses 4 and 5 are Λ and /! The radii of curvature r ₁ , r ", r ~ and r. the anterior and posterior surfaces of the respective lenses are then as follows:

ri = Ri / φι

■ r ₂ = Ri '/ Φι

^r 3 = β2 / Φ ₂

ri »= R ₂ ΥΦζ,

This way it is by building with two single lenses possible to determine the shape of each lens that has the coefficient of astigmatism II to achieve a good image quality and the distortion coefficient V, that of the elongation characteristic to achieve corresponds to a uniform scanning speed, also brings the corresponding desired values.

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Next, considering the direction perpendicular to the deflecting surface, it becomes the toric surface introduced and it is therefore possible to use different focal lengths of the lens 4 and 5 assembled System to be provided in the deflection surface. Hence is it is possible to have a different mapping relationship with respect to the mapping relationship in the deflecting surface to provide; the location of the reflective surface 3a of the deflector and the sensing material 6 become made conjugated.

Furthermore, what is important in the present invention, at least one surface of the single lens 5 with a toric surface has a negative refractive power in the cross section perpendicular to the deflecting surface. This contributes to the correction of the curvature of field, since the deflected in the cross section perpendicular to the deflection surface Light beam is caused to produce a good image spot

20 to form on the scanning material 6. If, in a cross section parallel to the deflecting surface, the radius of curvature r-, this surface of the single lens 5 has a toric surface which is adjacent to the deflecting element
is that relationship

²⁵ for ₃ > -2.1

with respect to the total focal length f of the spherical single lens 4 and the single lens 5 in this cross section is satisfied, the correction effect explained above is obtained

^{υ of} the curvature of field is greater. By this relationship it is meant that the scattering force for the incident light beam in the cross section perpendicular to the deflecting surface becomes stronger as the deflection angle increases;

This provides a correction effect for the curvature of field 35

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caused in a positive direction.

If further, in addition to the condition explained above

f / r_> - 2.1, the ratio f / f, between the focal P 3 pp

width of the single lens 5 with a toric surface in the cross section parallel to the deflecting surface and the focal length f, this single lens 5 in the cross section perpendicular to the deflection surface the relationship

f / P _n , <13.0,

is satisfied, it becomes possible to correct the elongation characteristic in the deflecting surface well.

It is also essential that in the cross section perpendicular to the deflecting surface, the shape of the individual lens 5 with a toric surface is desirably that of a meniscus single lens whose surface is covered with a positive refractive power is arranged adjacent to the scanning material 6 and the total has a positive refractive power Has. This makes it possible that the position of the main point of the spherical single lens 4 and the single lens 5 having a toric surface composite system in the cross section perpendicular comes to the deflection surface close to the scanning material. As a result of this, it becomes possible to arrange the entire lens system close to the deflecting element; through this

“ _{N the} result is a compact system. If the focal lengths of the entire system are f or f in the cross section parallel to the deflecting surface and in the cross section perpendicular to the deflecting surface, and if the condition 3.0 < ^f p / ^f _v = ⁵ · ^{0 is} met, the system becomes compact.

o, - Especially if the condition 4.0 <f / f _v ^ 5.0 ^

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is satisfied, the impact on the compactness of the system becomes great.

5 In the above equation (3), the desired value of the astigmatism coefficient to be corrected becomes II thereby determined whether the light beam incident on the reflection surface 3a of the deflection element 3 a divergent, a parallel or a convergent light-10 beam is on the deflecting surface. On the other hand will

the desired value of the distortion coefficient V to be corrected by the rotational characteristic of the deflector 3 determined.

When the deflector 3 at a uniform angular velocity is rotated, is the value of the distortion coefficient that causes that of the Deflection element deflected light beam on the surface of the scanning material 6 at a uniform speed moved: V = - = ·.

Since the movement of the deflection element 3 in the case of a sinusoidal oscillation is represented by φ = Φ sino3t, where ψ is the angle of rotation, <b is the amplitude, c *) is a constant related to the period of oscillation, and t is the time the value of the distortion coefficient which causes the light beam deflected by the deflecting element 3 to move at a uniform speed on the surface of the scanning material 6,

given by V = - | - (1 - ^ Λτ)

3 8φ2

Since in the context of this invention no condition for the collimation of the light beam between the spherical Single lens 4 and the single lens 5 with a toric surface is the degree of freedom for the refractive

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by virtue of each of the lenses is not limited and can have good image quality and elongation characteristics

can be obtained through these two lenses. 5

Embodiments of the spherical single lens 4 and the single lens 5 with a toric surface for the optical scanning systems according to the invention are shown below. Tables 1 to 12 show exemplary embodiments for the optical imaging system according to the invention 4, 5.

Among these tables, the tables marked with a character (a) indicate the lens data. r. to r. are 14th

the radii of curvature of the lenses in a plane parallel to the deflection surface, r 'to x. 'are the radii of curvature of the lenses in the cross section perpendicular to the deflecting surface (consequently for the spherical single lens 4: r. = r', r "= r"), cL is the axial 112 2 1

Thickness of the spherical single lens 4, ie the axial air gap between the surface of the spherical Single lens 4 and the r surface of the single lens 5 with a toric surface (the same as the axial Air gap between the r. -Surface of the spherical Single lens 4 and the rJ surface of the single lens 5 with a toric surface), d ,, is the axial Thickness of the single lens 5 with a toric surface, ■ n .. is the refractive index of the spherical single lens and n ~ is the refractive index of the single lens 5 with a ^

toric surface.

The tables marked with a character (b) are described below. In a plane parallel to "J. the deflection surface (hereinafter referred to as the "deflection plane"

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designated) and in the cross section perpendicular to the
From steering surface (hereinafter referred to as "vertical cross-section") the column f shows the focal length of the system composed of the spherical single lens 4 and the single lens 5 with a toric surface. To simplify the description, the focal length in the deflection plane is through f and the focal length expressed in the vertical cross section by f. the

Column f _c shows the focal length of the individual lens 5 with ⁵

a toric surface. To simplify the description, the focal length is in the deflection plane with
f. and denotes the focal length in the vertical cross section with f _r. The column bf shows the rear

Focal length. The column S ₁ shows the object distance from the ι ζ) ι

first surface (ie the r ₁ or r ₁ surface of the

spherical single lens). The column S, shows the distance from the last surface (r. Or r., - surface) of the single lens 5 with a toric surface to the Gaussian image plane when the object distance is S ₁ . The column 'itactual F-No. "Shows the actual
bilas-sided f-number when the object distance is S.

The tables marked with the character (c) show the tertiary aberration coefficients when f is 1 in dei

P plane is normalized parallel to the deflecting surface.

The tables marked with the symbol (d) are described below. The column d ~ shows the

oß Angle in the unit radian, which is determined by the

tJ surface of the spherical single lens 4 at a height 1 of the principal plane in the cross section perpendicular to the deflection surface containing the optical axis, the incident paraxial ray is formed when

or this beam on the r ~ surface of the single lens 5

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hits with a toric surface after having hit the Leave ι- surface of the spherical single lens 4

Has. If & f is O, the light beam will not be between

the r ~ surface of the spherical single lens 4 and the r 'surface of the face collimated.

r 'surface of the lens 5 with a toric upper

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Table 1 - (a)

co O O

ro

ο oo cn ro

ri -65.27560 r ¹ 1 -65.27560 di 6th .32971 ni 1. 59538 r ₂ -51.67753 r ' 2 -51.67753 d ₂ 6th .32971 Γ3 411.88135 r ¹ 3 -39.11693 d ₃ 6th .32971 Π2 1. 50991 ri » -86.20866 r ¹ 4th -12.20747

Table 1 - (b)

f
P. 99 f 140 ^f 5 b .f. ^S l 100 V actual
F no. Distraction plane ^f v 29 .99999 32 .40724 100 .12631 _ 00 99 .12631 60.0 ■ more vertical
! Cross-section . .48940 .23998 31 .32358 -26.79579 .60350 100.0

to

O co

CO

co

• co

DE 0634

Table 1 - (c)

I. II III P. V 6.46817 -0.28460 -0.16495 0.62416 0.61867

Table 1 - (d)

δ Max ri, / r 3 V ^r fi / fi ¹ 3.39105 -0.61374 29.15465 -0.20.931 0: 24279 4.35507

Table 2 - ( _a )

r ι -63.25409 r ¹ 1 -63.25409 di 6th .36775 ni 1 .70269 No. -52.72465 r ¹ 2 -52.72465 d ₂ 6th .36775 r 3 415.41869 r ¹ 3 -39.60989 d ₃ 6th .36775 n ₂ 1 .50991 rif -85.98748 r ¹ -12.30169

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Table 2 - (b)

f
P. . f .00001 ^f T fs 31518 b .f. Si 100 .69102 actual
F no. Distraction plane f
V 100 .54067 140 43860 100 .69012 - OO 100 .19817 60.0 more vertical
cross-section 29 32. 31 .54320 -26.95680 100.0

Table 2 - (c)

I. .11 III P. V 6.43969 -0.27146 -0.16089 0.60433 0.62013

Table 2 - (d)

δ ^E max r-Aa 0.24072 fi / fi ¹ V ^f v -0.61207 29.04269 -0.20699 4.32556 3.38516

Table 3 - (a)

r ι -65.40452 r ¹ 1 -65.40452 dl CTl 31236 Πι 1 .59583 χ ¹ 2 -51.14359 r ' 2 -51.14359 d ₂ 6th 31236 r ₃ 362.55977 r ¹ 3 -38.80420 d ₃ 6th 31236 1 .48330 r, -84.90856 r ¹ -11.70740

fa"

O ~ * to

O 6 »Ut to

Table 3 - (b)

f
. ' P. f O ^f T- fs .00551 b -f. Sl 99 89905 actual
F no. Distraction plane ^f v 100. 41967 143 .24268 99 89905 _ co 99 33635 60.0 more vertical
cross-section 29 32 31. 14615 -26.72231 100.0

Table 3 - (c)

U)

I. II III P. V 6.61678 -0.27837 -0.16698 0.63271 0.61596

CO Ό CD ■ CO ro

Table 3 - (d)

δ Max ri * / r ₃ ^f P ^{/ r3} fi / fi ¹ 3.39909 -0.61121 29.42713 -0.23419 0.27582 4.43529

Table 4 - (a)

co o ο

ro - »» ο oo cn NJ

T ₁ -58.82450 r ¹ 1 -58.82450 ^d i 6th .42988 ni 1 .50991 ^r 2 -50.19578 r ¹ 2 -50.19578 d ₂ 6th .42988 r ₃ 1690.12801 r ¹ 3 -42.23338 d ₃ 6th .42988 n ₂ 1 .70269 r ₄ -92.63733 r ¹ It -15.66758

I IO

Table 4 - (b)

f f
P. lOO.OOOOl fs ^f T 125.16837 b.f. Si ^S k ' actual
F no. ■ Distraction plane V 29.98307 V 32.22724 101.62692 - OO 101.62692 60.0 more vertical
cross-section 32.44994 -27.21982 101.19260 100.0

6 w

O σ \

U)

Ό CO

DE 06.3-4

Table 4 - (c)

I. II III P. y 5.99630 -0.22613 -α. 15095 0.56860 0.62777

Table 4 - (d)

δ ε
Max r ^ / r ₃ 0.05917 fi / fi ¹ " ^f p / ^f v -0.6 30 8 3 27.80320 -0.0-5481 3.88393 3.33522

Table 5 - (a)

ri -104 .13724 r ' 1 -104.13724 di 6th .25173 m 1. 595 Γ2 -69 .15419 r ' 2 -69.15419 d ₂ 6th .25173 r 3- OO r ' 3 -34.51051 d ₃ 6th .2517 3 n ₂ 1. 509 -7 3 .02843 r ¹ It -11.65612

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Table 5 - (b)

f
P. f 0 ^f T fs 21827 b .f. Si 99 .03431 actual
F-Ni. Distraction plane ^f v 100. 17851 f _T , 143. 59868 99 03431 - OO 98 .39212 60.0 more vertical
Queischqitt 29 31. 30th 68737 -26.46566 100.0

Table 5 - (c)

O O

O CD cn

j I II III P. V 6.27056 -0.32612 -0.15447 0.64372 0.59729

oo

Table 5 -

δ ε
Max r ₄ / r ₃ 0 .0 fi / fi ¹ 3.42718 -0.63,819 26.02809 0.0 4.53241

cn

OO

O Ca) CO

CD

Table 6 - (a)

ri -96 * 031.89 r ' 1 -96.03189 di ■ 6 .28837 ni 1 .70269 r ₂ -70 .08476 r ⁽ 2 -70.08476 d ₂ 6th .28837 r ₃ OO r ' 3 -35.28283 d ₃ 6th .28837 n ₂ 1 .50991 r ₄ -72 .33688 ig 't -11.76020

Table 6 - (b)

30012 Distraction plane f
P. f O fs 86205. b .f. Si 99 s _k , actually ·
F no. you ο more vertical
cross-section V ' 100. 22304 141, 72929 99 58740 _ CO 98 .58740 60 0 852 29 31. 30th 87595 -26.62078 .97599 100. 0

Table 6 - (c)

I. II III P. V 6.35924
. 1 1 ■ -0.29366 -0.15210 0.62596 0.59719

Table 6 - (d)

δ Max Wr ₃ 0.0 fi / fi ' V ^f v -0.61831 26.01836 0.0 4.47101 3.42196

Table 7 - (a)

co O O

IO

· »» ■■■

cn

ri -113.67176 Γ '1 -113.67176- CU 6.21517 ni 1.59538 r ₂ ■ ^ 70. 31723 r'2 -70.31723 d ₂ 6.21517 r ₃ OO r-3 -32.66198 d ₃ 6.21517 n ₂ 1.48330 r, -72.15232 r \ -11.04071

O I

■ Table 7 - (b)

f f
P. 100.0 fs b.f. Sl ^S k actual
F no. Distraction plane V 29.03092 98.50049 «. OO 98.50049 60.0 more vertical
cross-section 30.39421 -26.31088 97.81531 100.0 149.29096 31.55431

• ca ro ο

CTl

L)

-3T-

DE 0634

Table 7 - (c)

I. II III P. V 6.26524 -0.35871 -0.15356 - 0.65400 ; 0.59-321

Table 7 - (d)

δ "Max- Γι, / Γ3 ^f p ^{/ ri} fi / fx ¹ V ^f v -0.61339 25,752 82 O.Q 0.0 4.7312.4 3.44460

Table 8 - ta)

ri -63 .26744 r Ί -63.26744 αχ 6-. 43143 ni 1. 50991 r ₂ -53 .99132 r '2 -53.99132 d ₂ 6th 4 3-143 r ₃ OO r I. -42.55582 d ₃ 6th 43143 n ₂ 1. 70269 -8 6 .18348 r r
1" -15.64993

130Ö12 / 08S2

Table 8 - (b)

f f
P. 100.0 V fs b.f. Si V actual
.F-Ni. Distraction plane V 29.99780 122.64794 101.68839 - OO 101.68839 60.0 more vertical
Quei cut; 32.06282 32.41892 -27.22637 101.22387 100.0

C *> O O

ro 's *

00 cn ro

Table 8 - (c)

I. II III P. V 0.02252 -0.20250 r-0.14970 0.57056 0.62285

Table 8 - (d)

δ Max p.o V fi / fl ' ^f p ^{/ f} v -0.63597 27.22567 0.0 3.82524 3.33358

O ¹ CO O

CTl

Table 9 - (a)

ri -61.21937 r ¹ 1 -61 .21937 di 7th .49377 ni 1. 58611 r ₂ -55.26615 r ¹ 2 -55 .26615 d ₂ 7th .49081 r ₃ 2387.19485 r ' 3 -31 .67413 d ₃ 7th .49078 n ₂ 1. 53785 Do -66.80165 r ' * t . -11 .13852

CO O

JJk. N> S-.

OO cn ro

Table 9 - (b)

P. 99 f ^f T f
S. 94943 b. f. Si S. k ¹ actual
F no. Distraction plane f
V 26th .99935 120 32813 102. 54132 - OO 102. 54132 60.0 more vertical
,Cross-section .55801 28. 29 53442 -18.03525 101. 20096 100.0

IjO OJ

Table 9 - (c)

■ ι ΊΙ III P. V 7.40537
I. -0.38428 -0.11085 0.60322 0.60354

approx

CO CO

Table 9 - (d)

δ Max -0.02798 0.04189 fx / fx ¹ f / f
P ν -0.67218 27.76585 4.26959 3.76532

Table 10 - (a)

COi O O

OO cn ro

ri -49.46519 r 'ι -49.46519 dx 7.90475 ni 1.79136 r ₂ -53.94124 r «2 -53.94124 d ₂ 7.90470 r ₃ -611.60256 r 'a -35.89765 d ₃ 7.90469 Π2 1.55363 r ₄ -53.05425 r '/ + -11.55629

I OJ

Table 10 - (b)

f f
P. 100,00070 fs ^f T 104.40576 b.f. Si % ' actual
F no. Distraction plane V 25.86281 27.59081 107.93367 _ 00 107.93367 60.0 more vertical
' Cross-section 29.96403 -15.93758 106.74816 100.0

to CO

DE 0634

Table 10 - ( _e J

I. II III P. V 10.34164 0.23778 -0.10066 0.53930 0.59026

Table 10 - (d)

δ Max 0.08675 ^f P ^{/ r3} fi / fi ^{1 f} p ^{/ f} v ^: -0.70309 26.35079 -0.16351 3.78408 3.86658

Table 1t- (a)

-48 .90612 r'i -48.90612 _d _x 7th .90433 ni 1 .799 2 * r ₂ -53 .91277 r ' ₂ -53.91277 [ d ₂ 7th .90432 r ₃ -863 .5 & 893 r ' ₃ -35.97083 3 ₃ . 7th .90431 n ₂ 1 .5541 ' ri » r -53 .77089 r \ -11.54920 ■ -

130012/0852

Table 11- (b)

f ■ f 100,00078 fs ^f T 103.10964 b.f. Si V actual
F-Ni. Distraction plane P. 25.81655 27.51911 108.12026 - CO 108.12026 60.0 V f _T. 29.99749 -15.88357 106.67594 100.0 cross-section

Table 11 - (c)

I. II III P. V 10.01258 0.22663 -0.08551 0.53751 0.60134

Table 11 - (d)

""' 1
δ Max rt, / r ₃ f A ₃ fi / fi ¹ 3 _f 87351 -0.70478 26.91509 0.06226 -0.11597 3.74684

ό co co

Table 12 - ( _a )

-293.24044 r'i -293.24044 dl 5.88268 ni 1.59538 -59.23652 r ^f 2 -59.23652 d ₂ 5.88268 Γ3 -49.02234 Γ * 3 -10.76293 d ₃ ' 5.88268 Π2 1.50991 r " -41.48573 r \ -7.72696

Table 12

O O

cn

(b)

■ f M, 100.0 V fs b.f. Si V actual
. F-Ni. Distraction plane f
V 28.11088 418.80742 96.72185 - OO 96.72185 60.0 more vertical
cross-section 32.47258 31.07636 ' -24.90334 92.38294 100.0

OJ

Ö W

O cn ω

Table 12 - (c)

I. O II O III O P. O V 10 .70009 .50945 .06621 , 62788 .53405

Table 12 - (d)

δ. Max rn / r ₃ f Ai
P. fi / fi ¹ 3.55734 -0.52198 0.97507 0.84626 -2.03989 12.89726

Table 13 - (a)

ri -25 .067 rS -25,067 di 6th .329 ni 1 .78322 r ₂ -30 .314 r ' ₂ -30.314 d ₂ 18th .165 r ₃ CO r ' ₃ " -47,987 d ₃ 5 .414 n ₂ 1 .50991 r ₄ -47 .411 r \ -10,737

Table 13 - (b)

f
P. f .0 Λ fs .979 b. f. Si S. ' 1 actual
F no. Äblenk plane f
V 100 .452 f _T , 92 .857 116 .620 - OO 116 .620 60.U more vertical
cross-section 23 25th 28 .384 -5,681 117 .222 100.0

DE 0634

Table 13 - Cc)

I. II III P. V 9-. 300 1,558 -0.157 0.409_ 0.666

Table 13 - (S)

-
δ Max ri »/ r ₃ 0.0 ^f t / ^f t. 4,264 -0.730 26,231 ; 0.0 ..3,596

Table T4 - (a>

ri -25 .076 r ¹ 1 -25.07 6: di 6th .331 ni 1 .78322 r ₂ • -30 .J25 r ¹ 2 -30,325 d ₂ 18th .172 r ₃ - r ¹ 3 -48,151 d ₃ 5 .416 n-2 1 .48330 -44 .945 r ¹ 1" -10.29 2

130012/0852

Table 14 - (b)

⁵ p f .0 fs ^f T 92 .997 b. f. Si S. ¹ I. actual,
F no. Distraction plane V 100 .472 f _T , 25th .880 116 .635 -approx 116 .635 60.0 more vertical
cross-section 23 28 .372 -5,750 116 .164 100.0

Table 14 - (c)

I. II III P. V 10,606 1,742 -0.154 0.422 0.659

Table 14 - (d)

ό Max rc, / r ₃ 0.0 f _t / f _t , f / f -0.728 26,238 0.0 3,593 4,260

* '·· Table 15 - (a)

ri -25. 067 r'i -25,067 di 6th .329 ni 1. 78322 Γ2 -30. 314 r ^f 2 -30.314 d ₂ 18th .165 r ₃ co r ' ₃ -43,024 d ₃ 5 .414 n ₂ 1. 60770 -56. 476 r ' η -12,050

Table 15 - (b)

f
P. f .0 f 5 b .f. Si S. i ¹ actual
F no. Distraction plane f
V ■ ioo .434 92 .935 116 .565 - OO 116 .565 60.0 more vertical
cross-section
< 23 25th .837 28 .605 -5,681 117 .248 100.0

Table 15 - (c)

I. II III P. V 5,804 1,125 -0.138 0.366 0.690

Table 15 - (d)

δ ^£ max Γι, / Γ3 0.0 f _t / f _t , ^f _P ^{/ f} v -0.730 26,231 0.0 3,597 4,267

Table 16 - (a)

ri -20. 102 r Ι -20,102 di 5 .359 ni 1. 70916 r ₂ -24. 047 r ¹ 2 -24,047 d ₂ 14th .877 r ₃ OO r f -30,798 d ₃ 4th .697 n ₂ 1. 63398 r., -58, 485 r \ -10,614

Table 16 - (b)

M-I f
P. 100.0 fs ^f T 92,251 b.f. Si S ¹ I actual
F no. Distraction plane ^f v 21,316 23,431 115,545 - OO 115,545 60.0 ¹ vertical '
cross-section 26,079 -5,955 115,742 100.0

CTl U)

Table 16 - (c)

Table 16 - (d)

DE 0634

I. II III P. V 1.5 46 1,150 -0.113 0.325 0.657

Max r ^ / r ₃ ^£ P ^{/ r3} f _t / f _t . 4,691 -0.745 26,266 0.0 0.0 3,937

Table 17 - (a)

ri -23 .5 85 r 1 -23.5Φ5 dx 5. 424 m 1 .78322 r ₂ -27 .489 r 2 -27,489 d ₂ 15th 017 r ₃ OO r 3 -26,395 d ₃ 4th 375 n ₂ 1 .63398 r ₄ -60 .705 r 1" -10,024

130Ö12 / Ö8S2

Table 17 - (b)

f f
P. 100.0 fs ^f T 95,752 b.f. Si S ¹ I actual
F-Ni. Distraction plane f
V 21,126 23,098 113.356 - CO 113.356 60.0 ■ vertical
cross-section 25,481 -5,765 113,624 100.0

Table 17 - (c)

I. II III P. V 5,026 0.456 -0.099 0.375 0.646

Table 17 - (d)

δ Max Γι, / Γ3 0.0 f _t / f _t . 4,734 -0.745 26,272 0.0 4.145

O U) CO K) O

Table 18 - (a)

η -20 .009 r ¹ 1 -20,009 di 5 .403 ni 1 .70780 r ₂ -24 .039 r ' 2 -24,039 there 14th .958 r ₃ CO r ¹ 3 -30,842 d ₃ 4th .35 8 n ₂ 1 .63398 r " -58 .121 r ¹ -10,513

O O

N>

O OO cn

Table 18 - (b)

f f
P. 100.0 fs b.f. Si S'l actual, '
F-Ni. Distraction plane
'vertical -
cross-section V 21,110 115,836 - OO 115,836 60.0 25,793 -5,743 117.134 100.0 91,677 23,227

Table 18 - (c)

cn co

I. II III P. V 1,204 1,203 -Ό. 115 0.320 0.658

OJ

K) CD

Table 18 - (d)

S. ε
Max r ₄ / r ₃ 0.0 f _t / f _t , y ^f v -0.749 26,243 0.0 3,947 4,736

Table 19 - (a)

O O

N> 'S »

oo cn N>

-22 .097 r 'ι -22.097 dl 5 .401 ni 1 .73682 r ₂ -26 .738 r'2 -26,738 d ₂ 14th .953 r ₃ CO r'3 -29,941 d ₃ 5 .391 n ₂ 1 .60770 ri, -54 .394 r \ -10,134

(Tl I

Table 19 - (b)

f
P. f .0 ^f T fs • b. f. Si S ¹ I .733 actual
F no. Distraction plane V 100 .894 f _T , 89 .507 115 .733 - OO 115 .080 60.0 more vertical
cross-section 20th 22nd .858 25th .813 -4,706 117 100.0

to K) CD

D H

Df 0634

Table 19 - (c)

I. II III P. V 3,170 1,142 -0.123 0.362 0.662

δ ε Tabel 0 19 - (d) 0 As + J
M-I ^{/ f} f f P ^{/ f} v .755 26th Max Aa f .0 3. 916 4th .786 -O .381 .0

130012/0852

As shown in Fig. 4, the angle given by the normal (indicated by the broken line) to the r_ surface at the intersection between the deflected chief ray and the r_ surface of the single lens 5 having a toric surface is expressed as £ - (unit: degree, counterclockwise direction is assumed to be a positive direction); that of the maximum

Image height (= 0.5-f) corresponding angles is called f

ρ max

10 expressed. Fig. 5 shows the relationship between ε and

the image height in the embodiment shown in Tables 1- (a) - (d). Fig. 6 shows the relationship between £ and the image height for the one shown in Tables 12- (a) - (d) Embodiment. Fig. 7 shows the relationship

15 between £ and the picture height for the one in the tables 13- (a) - (d) illustrated embodiment.

As shown in Figs. 5 and 7, the in

the embodiments shown in Tables 1 and 13, if the image height is larger, C is also larger. That is, when the angle of incidence of observation is increased, the r _, surface of the lens 5 having a toric surface comes to have a higher refractive power for the light beam in the cross section containing the chief ray and perpendicular to the deflecting surface as compared with the case of one axial beam. This, combined with the effect of the r ^ -surface of the lens 5 with a toric surface, contributes to the correction of the curvature of the field, which causes the light beam deflected in the cross section to form a good image spot on the scanning material; the whole optical system after the deflecting surface has an elongation characteristic which has a uniform scanning speed on the surface to be scanned in the plane parallel to the scanning surface and the effect of correcting the drop in the cross section

130012/0852

perpendicular to the deflecting surface. In the embodiment shown in Table 12, the value of C is substantially in the region of θ " as shown in Fig. 6. In this embodiment, when the actual f-number is in the plane parallel to the deflector surface 60, the spherical aberration is equal to ■ * ■ 0.00037-fp, and if the image height is equal to 0.5 -f, the astigmatism is equal to -0.11 · f and LIN = 1.4, where LIN is a quantity that represents the linearity is ^,

V "" "f · e"

which is expressed by "linearity" = f * 9

ρ (y ¹ is the image height). Further, when the actual f-number is 100, in the cross section perpendicular to the deflecting surface, the spherical aberration is -0.0061-f, and when the image height is 0.5 »f, the astigmatism is -0.003-f. As shown in Table 12- (b), the difference between S, 'in the plane parallel to the deflecting surface and S,, in the cross section perpendicular to the deflecting surface is 0.0434.f. Accordingly, in this embodiment, in the plane parallel to the deflecting surface and the cross section perpendicular to the deflecting surface, the image quality of the optical scanning system according to the invention is considerably increased and is close to the diffraction limit. In this embodiment, f / r = -2.04 as shown in Table 12- (d).

Fig. 5A shows the shape of the lens design according to Table 1 in the plane parallel to the deflecting surface, and Fig. 8B shows the shape of the lenses of the same embodiment

^ in the cross section perpendicular to the deflecting surface. Fig. 9A shows the image errors in the same embodiment in the plane parallel to the deflection surface ^{un (} ^ Fig. 9B shows the image errors in the same embodiment in the cross section perpendicular to the deflection surface ..

130012/0852

-50- DE 0634

10A shows the shape of the lenses according to the exemplary embodiment according to Table 13 in the plane parallel to the deflecting surface and FIG. 10B shows the shape of the lenses of the same embodiment in the cross section perpendicular to Deflection surface. Fig. 11A shows the artifacts in the same Embodiment in the plane parallel to the deflecting surface and FIG. 11B the image errors in the same Embodiment · in the cross section perpendicular to the deflecting surface.

In FIGS. 9A and 9B and FIGS. 11A and 11B, as in column S,, of the corresponding tab with is shown by the character (b), the distance from the last surface (the r. or r ,, - surface) of the single lens with the toric surface to the Gaussian image plane different in the corresponding planes.

When considering the invention shown in Tables 1-19 Execution play is when the relationship is in the plane parallel to the deflecting surface between the radius of curvature r on the side of the deflector element, of the single lens 5 with a toric surface and the scanning material-side radius of curvature r. this lens same

l / ra> l / r-

and in this plane the radius of curvature on the side of the joint element r_ of the single lens 5 within the relationship

30 for ₃ > -2.1

to the total focal length f of the scanning lens system in

this plane lies, and the relationship between the focal length f of the entire system, which includes the spherical individual

Sr

or lens 4 and the single lens 5 with a toric upper

130012/0852

-51- DE 0634

area includes, in the plane parallel to the deflecting surface and the focal length f of the entire system in the cross section perpendicular to the deflecting surface equal to 3.0 <f _p / f _v <5.0,

and the relationship between the focal length f of the single lens 5 having a toric surface in FIG Plane parallel to the deflecting surface and the focal length f, the single lens 5 in the cross section perpendicular to P.

equal to the deflection surface

f _p / f _p , <13.0,

then the optical scanning system according to the invention in the Plane parallel to the deflecting surface an elongation characteristic, a uniform scanning speed on the scanning material 6 and perpendicular in the cross section to the scanning surface causes the effect of the correction drop.

In the above description, the sign of the radius of curvature is positive when the curvature is convex in the direction to the deflector, and negative when the curvature is concave to the deflector.

The following describes the position of the beam spot on the scanning material in the optical scanning system according to the invention to be discribed.

OQ Fig. 12 is a developed view of the cross section along the light beam in a direction perpendicular to the deflecting surface of FIG. 1. In FIG. 1, that of the Light source device 1 emitted light beam linearly near the deflection reflection surface 3a through the linear

nc imaging system 2 and will continue to the

130012 / 08S2

-52- DE 0634

Place 6a on the scanning material 6 through the overall system, which the spherical single lens 4 and the lens 5 with a toric surface. If the linear Imaging system 2 parallel to a point 2 'that passes through the dashed line is indicated, is shifted, i.e. when the linear imaging system 2 in one direction is shifted perpendicular to the optical axis and perpendicular to the longitudinal direction of the linear image, changes the light beam that goes through the linear imaging system 2, as indicated by the dashed line is and is imaged at the point 6b on the scanning material 6. That is, in that the linear imaging system 2 shifted in the direction perpendicular to the optical axis and perpendicular to the longitudinal direction of the linear image is, the image position, i.e., the location of the scanning line, on the scanning material 6 can be easily adjusted will. 13 and 14 show exemplary embodiments of the device for adjusting the scanning line position described above.

In Fig. 13, the direction indicated by arrow A is the direction perpendicular to the optical axis of the linear imaging system 2 and perpendicular to the longitudinal direction of the linear image. The linear imaging system 2 is in every other direction except in the direction of arrow A. immobilized by a frame 10; furthermore, the linear imaging system 2 becomes downward in the direction of arrow A pressed by a spring 11.

Consequently, by inserting or removing a

Adjustment plate 12 with a suitable thickness between a base plate 13 and the underside of the linear imaging system 2 any desired parallel displacement .in direction or of the arrow A of the linear imaging system 2 is achieved

130012/0852

, whereby the setting of the position of the scanning line can be done easily. In the embodiment shown in Fig. 14, the mapping system is linear 2 attached to a movable frame 14, which in turn is held in a groove 14 'of a base bed 15 will. According to the embodiment shown in FIG. Movement as · s in the direction of arrow A is prevented. To the Base bed 15 is attached a lead screw 16, which is screwably coupled to a nut 17 which is fastened to the movable frame 14. Deshaib can get through Turning a screw pin 18 the linear imaging system be moved as desired in the direction of the arrow A, so that the setting of the position of the scanning line is carried out can be.

Fig. 15 shows an embodiment in which the inventive optical scanning system is used in a laser beam printer. In Fig. 15, one of A laser beam generated by a laser oscillator 21 via a mirror 22 onto the entry opening of a modulator 23 directed. After being modulated by the modulator 23 with an information signal to be recorded has been, the laser beam forms a linear image perpendicular to the axis of rotation of a deflection element 25 near the deflecting reflective surface of the deflecting element due to a linear imaging system 24, the example includes a cylinder lens. The one through the deflection element 25 deflected beam is applied to a photosensitive Drum 27 through an imaging system 26, which has a spherical single lens 26a and has a toric single lens 26b, and probes the photosensitive drum · 27 at an even speed away. At 28 there is a first corona artery and

130012/0852

-54- DE 0634

at 29 denotes an AC corona discharger. These form a part for the electrophotographic process.

The laser oscillator 21 may be a light source device comprising a self-modulating semiconductor laser and an optical beam focusing optical system that changes the cross-sectional shape of the laser beam of the semiconductor laser
corrected and converts the laser beam into an afocal light beam.

In the application described above, it is not necessary that the spherical single lens 26a in the plane parallel to the deflecting surface incident light beam is always a parallel light beam, er can also be a divergent or a convergent light beam; the intention of keeping the light beam close to the reflective surface of the deflection element 25 in the cross section perpendicular to the deflection surface, can easily passed through a light source device 21

which comprises a light source and a condenser device as well as the linear imaging device 24.

Even if a

Light source like a semiconductor laser, in which the light emission angle in two different one on top of the other
perpendicular planes is different is used as the light source device 21 even if a rotatable symmetrical optical system is used as the line? .ies imaging system 24 by using the fact
that the emission points of the light source are different in two mutually perpendicular planes (this is equivalent to the fact that the object point has an astigmatism difference in two perpendicular planes, it becomes

130012/0852

possible to make the light beam close to the reflecting surface of the deflector 25 in the cross section is imaged perpendicular to the deflection surface, and that a divergent or a convergent light beam on the spherical single lens 26a in the plane is incident parallel to the deflecting surface.

A scanning optical system has been described above, which includes a light source section, a first optical imaging system for linear imaging of the light beam emitted by the light source section, a Deflection element whose deflecting reflection surface is close is the linear image formed by the first imaging optical system, a scanning material produced by the light beam deflected by the deflecting element is to be scanned, and a second optical imaging system disposed between the scanning medium and the deflecting element and in the order of the Side of the deflection element has a spherical single lens and a single lens with a toric surface.

130012 / 08B2

Blank page

Claims (1)

Rnuiiur - ICik-mli patent attorneys and OUHLING l \ lfcNS. ... Representative at PPfl Representative at EPA Grupe - Pellmann 3033207 0 ^ "" "- HTied'ke Dipl.-Chem. G. Bühling Dipl.-Ing.R. Kinne Dipl.-Ing.R Grupe Dipl.-Ing. B. Pellmann Bavariaring 4, Postfach 20 2403 8000 Munich 2 Tel .: 089-5396 53 Telex: 5-24845 tipat cable: Germaniapatent Munich September 3, 1980 DE 0634 patent claims 1. Optical scanning system with a decay correction function, characterized by a light source part (1), a first optical imaging system (2) for linear imaging of the light beam from the light source part, a deflection element (3), whose deflection reflection surface (3a) near the linear image formed by the first imaging optical system Is a scanning material (6) which is scanned by the light beam deflected by the deflecting element, and a second imaging optical system disposed between the deflector and the scanning material is and in the order from the deflecting element side a spherical single lens (4) and a single lens (5) with a toric surface. 2. Optical scanning system according to claim 1, characterized in that the lens with a toric surface is a meniscus lens with a positive refractive power and a surface with a negative ^ - refractive power on the side of the deflecting element and a * surface with a positive refractive power on the ^ Has side of the scanning material in a cross section which the optical axis of the spherical individual ^{V / 19} 130012/0852 Deutsche Bank (Munich) Account 51/61070 Dresdner Bank (Munich) Account 3939 844 Postscheck (Munich) Account 670-43-804 -2- DE 0634 lens (4) and is perpendicular to the deflecting surface through the deflector (3) deflected light beam is formed. 3. Optical scanning element according to claim 2, characterized in that the lens (5) with the toric surface fulfills _{the condition 1 / r-,> l / r 4,} where r_ is the deflector-side radius of curvature IQ in the deflection surface and r. the material side Is the radius of curvature of the lens. 4. Optical scanning system according to claim 2, characterized in that that in the deflecting surface the deflecting ^ 5 element-side radius of curvature r., Of the single lens (5) with a toric surface _{fulfills the condition fp / r -.> - 2 r} l, where f is the focal length of the second imaging optical system is in the deflection surface.
20th 5. Optical scanning system according to claim 2, characterized in that the focal length f "of the lens (5) with a toric surface in the deflection surface satisfies the condition f / f '<13 _; 0 fulfilled, where f is the focal length of the lens with a toric surface in a plane perpendicular to the Is deflecting surface and contains the optical axis of the spherical single lens (4). 130012/0852 -3- DE 0634 Optical scanning system according to one of the preceding claims, characterized in that the first optical imaging system (2) means for moving the position of the light beam spot on the scanning material (6) in a direction perpendicular to the scanning direction of the light beam on the scanning material having. 1 30012/0852